This invention relates to apparatus for locking semi-trailers and/or freight delivery units.
In the trucking industry, it is important that the contents of semi-trailers are secure from theft.
The most common approach has been to padlock the doors of the semi-trailer. Unfortunately, the lock remains accessible to thieves, who are able to cut the padlock with a pair of pliers or common tools.
It would be advantageous to have an apparatus for locking the doors of semi-trailers where the locking apparatus would be inaccessible to thieves.
It is an object of the invention to provide a locking apparatus which provides improved protection for the contents of semi-trailers and/or freight delivery units.
According to one embodiment of the invention, there is provided a locking apparatus for locking semi-trailer or freight delivery unit doors, comprising housing inserted through the floor of a semi-trailer and secured therein; plate means having a channel therein and positioned on the door of the semi-trailer adjacent to the housing; and pin means located within the housing, and being of a diameter less than the inner wall of the housing, and capable of moving from an unlocked position where the pin does not engage the plate means, to a locked position where the pin means engages the plate means such that the door of the semi-trailer or freight delivery unit can not be opened.
The pin means has at least one stop collar means located approximately mid-point along its length. A pin guide means is positioned towards the top of the housing and has a bore of sufficient diameter to permit passage of the pin means but not the stop collar means. Inner pin guide means is positioned towards the bottom of the housing, the pin guide means having a bore of sufficient diameter to permit passage of the pin means but not the stop collar means.
The pin guide means is positioned towards the top of the housing and secured on a pin guide seat means located below the top of the housing means.
The pin guide means and pin guide seat means have corresponding threaded bores through which a machine bolt means is threaded.
An optional spring means is positioned on the post means above the stop collar means.
A cam lock means is inserted in the bottom of the housing means until the cam lock means reaches the inner pin guide means, said cam lock means having a cam which engages a groove immediately below the inner pin guide means.
The housing means includes an upper adaptor means which fits over the top of the housing means, and a lower adaptor means which fits over the bottom of the housing means, the upper adaptor means and said lower adaptor means being welded into the floor of the semi-trailer.
Advantages of the invention are that the locking apparatus is inaccessible to thieves by being located in the floor of the semi-trailer and/or freight delivery units.